(from ohanian): a spaceship of frontal area 15 m2 moves through a large dust cloud with a speed of 2 x 106 m/s. the mass density of the dust is 7 x 10-18 kg/m3. if all the particles of dust that impact the spaceship stick to it, find the average decelerating force that the impacting particles exert on the ship. (you may assume that the mass of dust which sticks to the spacecraft is negligible compared to the mass of the spacecraft.)

Explanation:

Recognizing the data we have to,

So in this way we proceed first to decompose the variables,

The density is given by the formula

We also know that the Volume is given by

Where

Through this we relate volume to density

The momentum would be given as follows

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

if they have a finite resultant